IMAP clients—You can also access Gmail from several
other mail programs by setting them up as Internet Message Access
Protocol (IMAP) clients. These include Outlook, Outlook
Express®, Thunderbird®, Windows® Mail,
Apple® Mail, and more. Get started with IMAP.

POP clients—If your mail program can't be set up for
IMAP, you can set it up as a Post Office Protocol (POP) client instead.
Get started with POP.